Ronnie O'Sullivan hit the front before facing some overdue resistance as Mark Selby finally entered the battle in the Dafabet World Championship final.

For long periods there looked to be only one feasible outcome, as O'Sullivan homed in on a sixth Crucible title.

But from 8-3 he dropped four of the next six frames as Selby eased his deficit to 10-7 overnight, with the best-of-35-frame contest resuming on Monday afternoon before its evening finish.

The record books show O'Sullivan does not lose Crucible finals and on his return the 38-year-old will be armed with an advantage, which was his priority.

He secured it in sparkling fashion with a total clearance of 131 to lift the showpiece occasion from its mid-evening doldrums, nudging 9-5 in front, and followed that with 87 to go 10-5 clear with two frames still to play in the day.

Yet Selby saved his best for last, as breaks of 58 and 62 won him consecutive frames.

Until then, Selby had looked set for another savaging at the hands of the player who dealt him a 10-4 hiding in January's Masters final.

The 30-year-old from Leicester had a top break of 42 from the opening 11 frames, so to trail by only three and finish on such a high means he should return with a reinvigorated appetite for the challenge.

O'Sullivan's afternoon 102 and big evening century took his tournament tally to 12.

There was no disguising where Selby's second final, and first since losing to John Higgins in 2007, was going wrong initially.

C hances were coming his way but going begging, and his inability to score heavily when in the balls rendered him effectively uncompetitive against the world's best player.

There was the factor of the late finish on Saturday, after a 17-15 triumph over Neil Robertson in their semi-final, plus the day off O'Sullivan enjoyed after turning over Barry Hawkins with a session to spare, that meant perhaps it was inevitable Selby would struggle.

After O'Sullivan obliterated the challenges presented by Shaun Murphy and Hawkins in the previous two rounds, a third thrashing was regarded as an unlikely prospect.

The theory was that Selby was too tough a player to fold on the big stage, yet it does not require a great memory to recall that thumping Masters final loss.

If Selby was still bearing scars, he began to forget them towards the end of the evening.

O'Sullivan had delivered as high a tribute as he has perhaps ever paid Selby, when saying before the match that it was his opponent's temperament that set the bar.

Selby has become, O'Sullivan remarked, "the ultimate match player".

This particular contest became so niggly that three re-racks were required in the evening session, but O'Sullivan rose above the monotony, looking set to match Steve Davis' haul of six world titles and close to just one behind Stephen Hendry.

O'Sullivan has branded Selby both as "the torturer" and "a predator" in recent times, and come the final frames of day one he needed to live up to the billing.

That he did bodes well for the man seeking his first world title, but armed with a handy cushion O'Sullivan will still take some overhauling.